Effects of tritiated water on passivation behavior of SUS304 stainless steel

Oyaizu, Makoto; Isobe, Kanetsugu; Yamanishi, Toshihiko

The effects of tritiated water on the passivation behavior of SUS304 stainless steel were electrochemically studied by anodic polarization measurements and diachronic measurements of open circuit potential with changing tritium concentration and dissolved oxygen concentration as parameters in the electrolyte of 1N sulfuric acid solution, where the passivation inhibitory effects by tritiated water could be clearly observed. As a result, it was found that the passivation would be proceed with two steps. The effects of tritiated water could be observed in both of two steps; delay in the first step and deceleration in the second step. From these results, it was suggested that the passivation inhibitory effect might be promoted by further oxidation and sequential dissolution of Cr by radiolysis products.